Stalling Issue after Battery change, looking for answer

I put a new battery in my subaru and I'm experiencing some stalling issues. This problem has happened before when I lifted the terminals off the battery to clean off some corrosion.

 

When I come to a stop the engine drops to very low RPM's and usually rebounds to normal idling but sometimes it will stall. The first time this happened the problem seemed to go away on its own. Just looking for an answer to this issue. Is it possibly a computer reset issue?

 

I also am experiencing some "stuttering" issues in 2nd gear and only in 2nd gear. It seems to happen after I shift smoothly and get on the accelerator. It is very odd it feels like I'm driving a carburated engine and I'm just hoping it is not a sign of bad things to come. I have 116,000 miles on the car and everything is running strong, I'd hate to have issues now.

 

Thanks for any help/input.

I put a new battery in my subaru and I'm experiencing some stalling issues. This problem has happened before when I lifted the terminals off the battery to clean off some corrosion.

 

When I come to a stop the engine drops to very low RPM's and usually rebounds to normal idling but sometimes it will stall. The first time this happened the problem seemed to go away on its own. Just looking for an answer to this issue. Is it possibly a computer reset issue?...........

 

Try this:

Disconnect the negative lead for 60 seconds.

Reconnect neg lead, make sure both battery terminals are tight.

Insert key, rotate to ignition position.

Wait ten seconds, to allow "throttle initialization".

Rotate key to start position.

Mine always has a day or so of the idle dropping after the battery is disconnected. I think it's the ECU "learning" after the reset. I've never experienced a stutter however.

Unfortunately this does not sound like a battery issue. Nor does it sound like an ECU learning curve. The car should have default settings that would prevent it from stalling after the ECU has been cleared.

 

I would first check the fuel filter. It may be clogged and the car just isn't getting enough fuel at low speed. It could also been clogged injectors. After that, it could be any number of sensors or valves. You could try running a bottle of seafoam through the engine. If you have carbon build on on some of the sensors that would get rid of it.

car is manual? if so its just the ecu relearning. you have to adjust to it for a couple days. 2-3 days and it will be back to normal.

Thanks for the input guys. The car is manual and they are two separate issues sorry if I made them sound like they were linked together.

 

The stutter has been happening before I disconnected the battery terminals. I'll try some of the ideas stated above and see if anything helps. I'm sure there is some carbon build up since I have 116,000 miles on the car. A good cleaning and "tune-up" will probably do wonders.

 

Thanks.

use seafoam in the gas tank and use it through the vac line, 1 bottle for each. Start the car, disconnect the brake booster vaccum hose going to the master cylinder, place tip of hose in a bowl of seafoam allowing the engine to suck it in, only a little at a time so the car stays running, empty the whole bowl(entire can). Maybe get a friend to lightly give it gas to rev it up a little, to about 1000rpm. It will blow blue/white smoke during this and shortly after, no worries. Once done drive it around with highway and it will clear. It removes carbon build up in the valvetrain improving idling and smooth operation of the engine mechanical valves. Seafoam can be had at autozone, and pretty much every chain auto store.

 

sounds like you have a fuel delivery issue, maybe the fuel filter is clogged if it dies at idle.

This stalling issue is pretty much exactly what I'm experiencing right now as well. The dealership reset the ECU when changing the seat belt sensor and ever since I've had idle dips. It only happens right when I let the revs drop. If it's still running after the initial dip, it almost always returns to a normal idle.

 

After looking around here a bit and talking to my service writer, it seems like the throttle body and or idle control valve is dirty. I'm not sure when I'll be able to get in there to clean it up, but in the meantime, I used my AccessPort to jack up the idle and it at least keeps it from stalling.

When you install a new battery, or have it disconnected, the ECU get's all kinds of fault codes and will do all kind of 'funny' things to safe the engine.

You will be surprised how many you have when you hook up the OBD-II.

 

 

Just have the ECU fully reset, and the list is clean again.

 

Normally the ECU needs about a day then to come back to it's normal ignition-timing. You can bypass this by the following trick:

 

Drive in second or third gear, and try to hold 3000rpm while breaking constantly for about 20 seconds.

When you install a new battery, or have it disconnected, the ECU get's all kinds of fault codes and will do all kind of 'funny' things to safe the engine.

You will be surprised how many you have when you hook up the OBD-II.

 

 

Just have the ECU fully reset, and the list is clean again.

 

Normally the ECU needs about a day then to come back to it's normal ignition-timing. You can bypass this by the following trick:

 

Drive in second or third gear, and try to hold 3000rpm while breaking constantly for about 20 seconds.

 

Well, if the battery was out of the car for more than about 10 minutes during the swap, your ECU is fully reset anyway.

It's not clogged injectors, or a clogged fuel filter, its just the ecu relearning. Don't do anything crazy, just give the ecu some time to relearn.

It's not clogged injectors, or a clogged fuel filter, its just the ecu relearning. Don't do anything crazy, just give the ecu some time to relearn.

 

I can't speak for the OP, but mine has been relearning for several weeks and at least a thousand miles and is still stalling occasionally.

I can't speak for the OP, but mine has been relearning for several weeks and at least a thousand miles and is still stalling occasionally.

 

 

how long did you let the car idle for after starting it for the first time? If its still stalling, i would reset the ecu again, and let it idle for 10 minutes before driving for the first time.

 

--The reason I doubt the OP is having fuel issues is because he made no indications that the car was acting funny before the battery change. So lets be honest, it would be quite the coincidence for them to start happening after installing a new battery. Possible? Yes,but I would consider other possible issues first.

how long did you let the car idle for after starting it for the first time? If its still stalling, i would reset the ecu again, and let it idle for 10 minutes before driving for the first time.

 

--The reason I doubt the OP is having fuel issues is because he made no indications that the car was acting funny before the battery change. So lets be honest, it would be quite the coincidence for them to start happening after installing a new battery. Possible? Yes,but I would consider other possible issues first.

 

Well, that's exactly what happened in my case as well, the car was behaving just fine, I took it in because the sensor in the driver's seat belt buckle was defective, and when I got it back it was stalling and has been ever since. I agree that it's a learning issue, but there is clearly something aggravating it, or it would be able to learn that it's not supposed to idle at 300 RPMs pretty rapidly. At the same time, I do not believe it's a fueling issue, so we agree there.

I've never tried this on a subaru.. but we get weird issues with VW's all the time when doing batteries. VW tech line has us do a "capacitor discharge" which is disconnecting both terminals from the battery waiting about 2 mins, then connecting both terminals (still disconnected from battery) together with a jumper lead. Let it sit for about 15 mins. Then reconnect. Again this is something we do all the time on VW's, i dont know if it will work do good or harm to a subaru. but just an idea.

I've never tried this on a subaru.. but we get weird issues with VW's all the time when doing batteries. VW tech line has us do a "capacitor discharge" which is disconnecting both terminals from the battery waiting about 2 mins, then connecting both terminals (still disconnected from battery) together with a jumper lead. Let it sit for about 15 mins. Then reconnect. Again this is something we do all the time on VW's, i dont know if it will work do good or harm to a subaru. but just an idea.

 

From an electronic point of view, that makes sense. Someone who is changing batteries fairly regularly can probably do it faster than the decoupling capacitors in the ECU can fully discharge. So it probably happens occasionally that they'll discharge to a voltage just low enough for some of the memory to erase and leave the rest intact, which would be a very bad situation in which to start your engine. Much better to discharge the caps completely and thereby erase everything and start from scratch.

 

In my case, I have reset the ECU using a scantool, so a discharge should not be necessary, but if I can't find anything else wrong, I'll try bussing the leads together. BTW, this isn't something that should harm any car, unless you have amplifiers and/or giant caps on your sound system. Your TSB is telling you to wait a few minutes before you buss the leads. This is to allow the caps to discharge somewhat naturally before you short them out, which could otherwise cause damage to the caps and in rare cases, cause them to short internally and ignite the next time you apply power. A lot of people perform this discharge by pressing the brake pedal for about 30 seconds with the battery disconnected. This allows any charges in the system to be dissipated through the brake lights, rather than dumping 100% of that charge through a 0 Ohm load, which is ultimately safer for any installed electronics.